Wiring Problems

[Gemini]

Truck is a 2000 RCSB. Started life as a 4.3 currently has an 04 LQ9 with 04 harness and ECM. I am getting zero power to the starter and gauges are gone. No message center, voltage reads zero, temp reads 190. Fuel pump primes and all other electrical works. I still have the 2000 4.3 fuse block in the truck. Does this need to change? Any help is greatly appreciated.

[Gemini]

I've been reading into this more and it sounds like I have to identify and relocate a few wires on C2, C100, and C152 plug. I found a great list on lt1swap.com that shows the pinouts for the 00' and 04' trucks along with circuit number, wire color, and function. I will be working on it this weekend and I'll keep everyone posted.

[farmtruc]

So it's drive by wire?
If you turn the key to ON position, do you have throttle body movement when pressing the pedal?

IF the starter has no power, trace it from the fuse block down to the PRDL switch, those two could be related. if the trans isn't in P/N it won't start, and if the wires are gone due to the swap.

Once the starter turns over, then as it's cranking check for rpm or crank signal, it all starts there.
Make sure there is spark and injector activity.

[Gemini]

I haven't checked if I have throttle body movement or not actually. My truck was a manual in the beginning so I'll have to learn how the neutral safety switch works. I had the V6 fuse block plugged in and hit the key and about half of my gauges lit up but my voltage gauge was dead and I had no message center. I know this is due the fuse box wiring being different between the two motors. My debate was wether I should use the V6 fuse box and repin the wires to the motor or use the v8 fuse box and repin everything but the wires to the motor. I apologize for leaving everybody in the dark on this one for a couple days. I bought the ALLDATA manual on Saturday for my 2000 and for the 04 that the motor came out of. I got a newer fuse box out of an 03 v8 sierra and went to swap some wires. A minute into reading the alldata connector view for my truck I realized it was wrong. A1 and A2 according to the manual are pink and brown and mine were both orange. After seeing this I stopped. I would assume that even though the wires are different color that they would still have the same function but I wasn't sure. It's raining here today so I'm going to see if I can push it into a shop and start working on this again. I'm going to use the 03 v8 fuse box and tag and label all of the wires I remove and go off of the alldata manual as if it were 100% correct and see what happens.

Thanks for the help Farmtruc

[farmtruc]

Both transmissions will use a safety switch and both can be bypassed.
Probably check your clutch pedal for a switch, you can bypass it if you don't care for the safety.

as for gauges, you'll just need to verify and double check all your wiring.

i would make it as oem as possible, so you can troubleshoot easier if needed.

all dlc pinouts for serial data, chevy, will be the same, two grounds, battery, data line. the pin location stays the same.

[Gemini]

So I tried to repin the 04 c2 engine harness to match the 2000 v6 fuse box.

IMG_2351.jpg

Everything matched up except for F3 Crank Voltage wire, a ground, and one 02 plugin that is fixable. The v8 harness only had 1 ground and my v6 block had a spot for 2 grounds in D12 and F7. I turned the key and no luck.

This is what my dash currently looks like with the key on.

IMG_2353.jpg

I would definitely like to bypass the neutral safety.

And I definitely would like to keep it as oem as possible.

At this point I am considering going DBC and using the 99-02 harness. I'm sure I can get a 2000 4.8L 5 speed harness for pretty cheap along with a DBC TB.

I saw on here that ALLBLACKSIERRA has the same setup as me with a 2000 truck and an 03 v8. He wound up using the 03 fuse box and rewiring the a few plugs to match. I have an 03 fuse box on hand and will give this a try.

[Gemini]

Sounds like AllBlackSierra had to mess with the BCM and I/P wires to get going. He got his running. I really don't want to mess with the BCM though.